Pressure on the nerves or blood vessels in the neck may be diagnosed as thoracic outlet syndrome, a condition that causes tingling, numbness and other symptoms in the arm. Triple board-certified plastic and reconstructive surgeon, John R. Barbour, MD, FACS, is a fellowship-trained hand and peripheral nerve specialist who offers thoracic outlet syndrome (TOS) diagnostic and treatment services for residents of the Washington, DC, area, including Fairfax, Arlington, Alexandria and surrounding areas of Virginia.
What is Thoracic Outlet Syndrome?
Thoracic outlet syndrome (TOS) is a condition that causes arm pain, numbness, tingling, and weakness. The symptoms stem from pressure in the neck that blocks the nerves and/or blood vessels that go to the arm. There are two main types of TOS — neurogenic and vascular (arterial or venous). Neurogenic TOS nerve compression is the most common type of TOS. It is important to separate the types of TOS to diagnose a patient appropriately. In some cases, a patient may exhibit symptoms of both types of TOS. In these cases, Dr. Barbour will work alongside a vascular surgeon to ensure that both causes of the symptoms are addressed.
What Causes Thoracic Outlet Syndrome?
Neurogenic TOS is often caused by neck trauma, whiplash injuries or a repetitive stress injury at work being the most common events that bring on symptoms. Often the injury results in over-stretching neck muscles that heal by forming scar tissue in the muscle. This, in turn, puts pressure against the nerves to the arm and causes the symptoms.
Vascular TOS is often caused by strenuous use of the arm, which irritates the main vein to the arm lying behind the collar bone. Pressure against the vein can be due to variations in anatomy. Most people have adequate room for the main vein to travel from the arm to reach the heart. However, some people are born with a very narrow space through which the vein travels. People in this category can develop obstruction and clots in the vein from excessive arm and shoulder activity.
What are the Symptoms of Thoracic Outlet Syndrome?
Common symptoms of Neurogenic TOS include:
- Tingling in the hand and arm
- Neck pain or pain in the back of the head, in some cases
Common symptoms of Vascular TOS include:
- White discoloration of the hand or arm
- Cramping of the hand and forearm with activity
How is Thoracic Outlet Syndrome Diagnosed?
Neurogenic TOS is diagnosed by using provocative maneuvers to provoke symptoms to appear. These maneuvers put the neck and arms in certain positions, which puts stress on the nerves to the arm to bring on the symptoms of pain, numbness and tingling in the hand, arm, and neck.
Few tests are helpful in making the diagnosis of neurogenic TOS. The most helpful test is a scalene muscle block. This is performed by injecting a small amount of local anesthetic directly into the scalene muscles of the neck. A positive response is an improvement of symptoms at rest as well as with the provocative maneuvers that occur within one or two minutes of the injection.
Nerve tests such as EMG and NCV tests are usually normal. The one exception is people who have an extra rib (cervical rib) plus arm weakness and atrophy of the hand muscles. This group usually has abnormal nerve tests indicating ulnar nerve abnormalities. However, the recent introduction of a new nerve test, the MAC test (abbreviation for medial antebrachial cutaneous nerve) has proven to be very useful, particularly in people who have symptoms in just one arm. In these cases, the good arm serves as a baseline from which to compare the symptomatic arm.
X-rays are usually normal but are worth obtaining as they may demonstrate an extra rib in the neck (cervical rib). While less than 5 percent of people with neurogenic TOS have an extra rib, when present it is helpful in confirming a diagnosis. Newer diagnostic tests that have yet to prove themselves include MRI of the brachial plexus and injection of dye around the brachial plexus (neurography). The problem with the latter tests is that many healthy individuals demonstrate abnormalities with these examinations.
Arteriography is helpful in the diagnosis of arterial TOS but should not be used to diagnose neurogenic TOS. The reason is that healthy individuals can reveal narrowing in the artery when the arm is elevated. This makes demonstrating the narrowing of an artery to the arm in patients with nerve symptoms of no value in the diagnosis of a nerve problem.
Recognition of arterial and venous TOS is usually not too difficult, as there are objective tests available to confirm the diagnosis and there are very few other conditions that resemble them. However, neurogenic TOS, by far the most common type of TOS, is more difficult to diagnose because other neurogenic conditions mimic it. An understanding of the anatomy of nerves to the arm is helpful. A nerve is like a telephone wire running from a telephone pole down the street into your house. Damage to the wire anywhere along its course will produce the same result, namely cutting off the phone you pick up. Nerves to your hand begin in the neck and run to the fingers like a single wire. Pressure against the nerve anywhere along its course will produce the same symptoms in the hand, namely numbness, tingling, pain, and weakness. The pressure points where this is likely to occur are at the wrist causing carpal tunnel syndrome; in the forearm producing pronator or radial tunnel syndrome; at the elbow against the ulnar nerve causing cubital tunnel syndrome; below the collar bone under the pectoralis minor muscle eliciting pectoralis minor syndrome; at the side of the neck causing thoracic outlet syndrome; or in the cervical spine produced by cervical disc disease or cervical arthritis.
Therefore, the pressure at any of these points elicits symptoms similar to neurogenic TOS, and each of these conditions must be looked for on physical examination and tested for by diagnostic nerve studies. To make diagnosis even more confusing, these other conditions can exist along with neurogenic TOS as associated conditions (called double crush syndrome) or they may be the primary diagnosis instead of neurogenic TOS.
Venous TOS can be more easily recognized by swelling of the entire arm and hand. Superficial veins that lie just under the skin are more prominent in the involved arm, shoulder, and over the chest wall of the involved side. The only tests that help diagnose venous TOS are doppler or duplex examinations and venography, where dye is injected into the vein of the arm.
Arterial TOS is recognized by a hand that is colder and paler than the opposite normal hand of that person. The pulse at the wrist is usually diminished or absent.
Tests helpful in the diagnosis of arterial TOS are non-invasive pulse-volume recordings (non-invasive vascular lab studies) and arteriography (injecting dye into the artery).
What is the Treatment for Thoracic Outlet Syndrome?
There are essentially two ways to treat TOS: non-surgical, which is called conservative, or surgical. Neurogenic TOS is always initially treated with physical therapy. Many patients improve with this treatment, and nothing further is needed. However, neurogenic TOS can be treated surgically if conservative therapy fails and a patient is still having significant symptoms. Surgery involves removing pressure from the nerves to the arm by either removing the scalene muscles in the neck, removing the first rib which requires detaching the scalene muscles or doing both scalene muscle and first rib removal. Vascular TOS is surgically treated by first rib resection including removing the bands and ligaments that surround the restricted vessels.
If you have symptoms of thoracic outlet syndrome, Dr. Barbour can evaluate your symptoms and provide you with an accurate diagnosis of the condition, as well as explain your treatment options. Contact us today to schedule a consultation.